/**
 * Copyright (c) 2010 by Kevin Bierhoff.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *    1. Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *    2. Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *    3. Neither the names of the authors nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ''AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package com.googlecode.syper.anno;

/**
 * @author Kevin Bierhoff
 * @since Jan 17, 2010
 *
 */
public abstract class Pred {

	/** Quantified integer predicate */
	public interface IntPred {
		/** Condition predicated by the given integer */
		@Imm public boolean cond(int arg);
	}
	
	/** This method allows making an assumption */
	public static boolean assume(boolean assumption) {
		assert assumption;
		return assumption;
	}

	/** This method defines a method pre-condition */
	public static boolean requires(boolean pre) {
		assert pre;
		return pre;
	}
	
	/** This method defines a method post-condition */
	public static boolean ensures(boolean post) {
		assert post;
		return post;
	}
	
	/** This method marks a loop invariant */
	public static boolean inv(boolean invariant) {
		assert invariant;
		return invariant;
	}
	
	/** Universal quantification over integer range */
	public static boolean forall(int start, int end, @Imm IntPred all) {
		for (int i = start; i < end; ++i) {
			if (! all.cond(i))
				return false;
		}
		return true;
	}
	
	/** Existential quantification over integer range */
	public static boolean exists(int start, int end, @Imm IntPred ex) {
		for (int i = start; i < end; ++i) {
			if (ex.cond(i))
				return true;
		}
		return false;
	}
}
